It is known in the printing industry to use spray heads to deliver fluid to a plate cylinder. Spray heads include spray nozzles which are modified to spray a certain type of spray distribution. However, each spray nozzle works in conjunction with the spray head which includes a valve body and solenoid for the delivery of the fluid. Thus, the desired spray distribution is achieved, in part, by the operation among the spray nozzle, valve body and solenoid. Further affecting spray distribution is the geometry of the valve body.
In addition, typical prior art spray heads have a lag time from the time when the solenoid valve is turned off to the time the fluid stops being ejected from the tip of the spray nozzle. This lag time increases with increased volume in the spray nozzle cavity. Moreover, during this time, the fluid pressure is lower than desired and does not generate a fully developed spray distribution pattern. This creates a situation where more fluid is sprayed from the center of the spray nozzle than from the edges, resulting in a non-uniform lateral distribution.
In an attempt to decrease lag time, prior art arrangements have minimized the volume of the fluid in the area between the valve and the tip of the spray nozzle. Prior art arrangements have tried to decrease the size of the orifice in the valve body and have tried to fill the volume of the back cavity of the spray nozzle with a nipple featured on the valve body. Unfortunately, these arrangements tend to direct the fluid straight through the center of the tip of the spray nozzle, thus preventing a fully developed spray pattern from being generated.